Injecting combustible fluids and coolants into combustion chambers has long been a common practice in the prior art. Typically, fuel and oxidizer reactants are brought to an injector face by separate flow paths. The reactant flow paths are designed to control and meter the fluids prior to their exit from orifices in the injector face. Internal geometry, spacing, and number of the orifices are configured to promote efficient mixing as the combustible fluids flow into a combustion chamber and travel away from the injector face. An ignition source then ignites the combustible mixture of reactants and large quantities of heat are released.
The large heat release in the combustion chamber usually makes it necessary to actively cool its walls to prevent combustion chamber damage. This is typically accomplished by enveloping the parts of the chamber to be cooled with a coolant, generally a fuel or water. Often more cooling capacity is necessary, as when stoichiometric mixture ratios cause extremely high combustion temperatures. In this case, coolant is injected directly into the combustion chamber and mixes with the combustion fluids. Cooling systems such as that disclosed by Walker (U.S. Pat. No. 2,770,097 are of this type. are of this type.
There are several drawbacks to the prior art approach. First, stoichiometric mixture ratios are generally not used because of the excessive heat generated (as well as pollutant generation problems), thereby limiting the heat release of the reactants below their full potential. An important reason reactants are not combusted at stoichiometric mixture ratios is that high levels of cooling are required to prevent damage to the combustion chamber and injector face. Another important reason is that a catastrophic explosion could result if the combustion flame propagated back into the injector body.
The second drawback to the prior art approach is that the mixture ratio distribution within the chamber is often not uniform. The non-uniformity occurs because machining tolerances permit variations in the orifice geometry and spacing and because manifold velocities are often not uniform. This leads to streaking of the combustion walls and necessitates the use of a chamber wall film coolant. The coolant, generally fuel, reduces the overall combustion efficiency of the process and results in using more fuel than otherwise would be necessary.
Beichel (U.S. Pat. No. 5,709,077) teaches a prior art system which disclose combusting hydrocarbon fuel with oxygen at a stoichiometric ratio to produce a high temperature water and carbon dioxide working fluid without any pollutants. This system teaches water delivery to cool the combustion reaction somewhat. However, no system for injecting the reactants and water into the combustion chamber is shown other than direct entry into the combustion chamber as disclosed in the prior art.
Accordingly, a need exists for an apparatus and system that thoroughly mixes the combustible fluids and allows combustion of fuels at stoichiometric mixture ratios without damaging the combustion chamber or incurring undesirable combustion inefficiencies.